The noise is much louder. The resonator acts like a glass pack to reduce sound. I have only had it done for 3 days. On the 2nd day, I sort of blew my motor, so its in my driveway waiting for Monday to go to the dealer. I passed a few cops, and they didn't say anything. As long as you are not acting stupid/obnoxious with it, you should be ok. I got a carsound High-Flow cat. It may feel slower when you first get it on, but once you break it in you will have a good increase. I recommend the header next, thats in the mail for me. Having a complete aftrermarket exhaust, I think you can get 20 hp. I will dyno after I get the header on and back from the shop. If you have any more question, just ask.